Calculating the sense of buying a 7 or 14 day ticket

Hi

My husband and I are arriving in Tokyo at Narita International Airport on 12 May 2025 and will be staying in Tokyo until 16 May when we travel to Kyoto where we will be staying until 18 May then on to Osaka and then on 20 May from Osaka to Hiroshima. In between we may go to KAWAGUCHI LAKE if the weather is nice. Then we return to Tokyo and go to the airport on 23.5. to finish our trip. Which train ticket should I buy, each day separately or 7 days or what?

thank you in advance
Anita from Slovenija